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 ###Instrução: Quantas classes AA no ano de 2002-03.
 ###Tabelas: CREATE TABLE women_kayak (women_kayak_id AUTO_INCREMENT PRIMARY KEY, Distance VARCHAR, Event VARCHAR, Record VARCHAR, Nationality VARCHAR, Year INT, Location VARCHAR) CREATE TABLE 2012_statistics_at_least_1000000_passengers_incomplete (2012_statistics_at_least_1000000_passengers_incomplete_id AUTO_INCREMENT PRIMARY KEY, Country VARCHAR, Airport VARCHAR, City VARCHAR, 2012 INT, Change (12/11) VARCHAR) CREATE TABLE list_of_prior_winners (list_of_prior_winners_id AUTO_INCREMENT PRIMARY KEY, School Year VARCHAR, Class A VARCHAR, Class AA VARCHAR, Class AAA VARCHAR, Class AAAA VARCHAR, Class AAAAA VARCHAR) CREATE TABLE average_chart (average_chart_id AUTO_INCREMENT PRIMARY KEY, Rank by average INT, Place INT, Couple VARCHAR, Total INT, Number of dances INT, Average INT) CREATE TABLE united_kingdom_channel_4 (united_kingdom_channel_4_id AUTO_INCREMENT PRIMARY KEY, Episode number INT, Title VARCHAR, Original airing on Channel 4 VARCHAR, Time of airing on Channel 4 VARCHAR, Original airing on E4 VARCHAR, Time of airing on E4 VARCHAR, Position in Channel 4s ratings a VARCHAR, Position in E4s ratings b VARCHAR, Total viewers VARCHAR)  
SELECT COUNT Class AA FROM list_of_prior_winners WHERE School Year = 2002-03